Printing-press



(No Model.) 2 Sheets-Sheet 1. J. F. W. DORMAN.

PRINTING PRESS.

No. 495,832. Patented June V25, 1889.

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PRINTING PRESS.

No. 405.832. Patented June 25, 1889.

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UNITED STATES PATENT OFFICE.

JOHN F. IV. DORMAN, OF BALTIMORE, MARYLAND.

PRINTING-PRESS.

SPECIFICATION forming part of Letters Patent No. 405,832, dated June 25,1889.

Application filed October 29, 1887. Serial No. 253,698. (No model.)

. specification.

This invention relates to certain improvements in a locking device tofirmly hold the platen and bridge in place while the impression is beingmade, and to counteract the tendency of the platen to tilt when the typeor form is placed either above or below the center of the bed.

It further relates 'to means for guiding the movement of the bridgeduring the locking operation, as will hereinafter fully appear.

In the further description of the said invention which follows referenceis made to the accompanying drawings, forming a part hereof, and inwhich Figure I is an exterior side elevation of certain parts of aprinting-press embodying my improvements. Fig. II is a sectional sideelevation of certain parts of the improved press. Fig. III is a frontview of Fig. I with certain parts thereof removed. Fig. IV is a sideview of a part of the invention.

Similar letters of reference indicate similar parts of the invention inall the views.

In the said drawings, A is the frame of the press, and B thedriving-shaft, to which power is applied.

C is the shaft from which the bridge, hereinafter described, receivesits motion, and it is driven from the shaft B through the medium of thegears D and E.

F is the bed of the press, and G the platen, which in constructiondiffers in no essential particulars from those usually employed inprinting-presses.

H is the bridge, and I the front shaft, adapted to turn in the bridge,and to the ends of which the draw-bars a are attached. These draw-barsconnect the front shaft with pins bin the gear-wheel E, and at the pointof connection between the said bars and the gear E are employed cams orgrooved disks 0, the construction of which is common and requires nodescription herein. The bridge 11 is provided with rockers (Z, whichrest and rock on the frame A, and also with extensions e, which, inconnection with a bar f,

forms a lock, hereinafter more particularly described.

The bar f is confined between and connects the two sides of the frame A,(see Figs. II and 1H,) and the extensions 6 of the bridge are furnishedwith cap-pieces g, having lips h, adapted to fit over the upper side ofthe said bar. (See particularly Figs. I and II.) In the latter figurethe bridge is shown as tilted back, and the extensions with the capsdisconnected from the barf.

The tilting motion of the bridge is usually obtained by means of a rodi, which unites that device with the barf, and in order to admit of thelocking of the bridge as pressure is applied and the face of the platenbrought in contact with the form, this rod t' is made extensible and aspring employed to cause it to assume its normal length when pressure isremoved and the bridge thrown back. This extensible spring-bar iseffective as long as the spring therein is unimpaired; but should thespring be broken there is nothing to make the bridge rock on the frameand bring the platen into avertical position or prevent its slidingforward and coming in contact with the bed and breaking the press. Toobviate this difficulty, I pr0- Vide the outer side of the rockers ofthe bridge with pins j, carrying rollers k, and the frame with the lugsJ, which have each a horizontal groove Z and an inclined straight face Zextending therefrom. The said grooves extend toward the bed of thepress, and the inclined straight faces l fall back from the point atwhich they intersect the said grooves. (See particularlyFigs. II andIV.) Supposing the bridge to be in the position shown in Fig. II, therollers kbear against the inclined faces Z of the lugs J. In themovement of the bridge and platen toward the bed the pins and rollersdescend the inclined straight face, and finally, as the bridge andplaten assume a vertical position, enter the grooves l, and remain inthem until the impression is made. During the last part of thehorizontal movement of the rollers in the grooves l the lips h of thecaps g on the extensions 6 of the bridge are drawn over the barf, andthe bottom side of the bar comes in contact with the upper face of theextensions. By this arrangement the bridge is firmly locked. The

extensible bar 'i, while not necessary to effect the proper movement ofthe bridge when the rollers and grooved lugs are employed, serves tosteady the movement of the bridge, and by the action of the spring inthe said rod the weight of the bridge while in its lowest position iscounterbalanced.

From the foregoing it will be seen that the bridge, which is generallyguided in its rocking or tilting movement by means of the extensible bar2', has wit-h my present invention a positive movement, which is notdependent upon the action of any spring mechanism, and therefore notliable to disarrangement, the said spring-bar being used merely as anauxiliary device, which may be removed without materially affecting theaction of the press.

By having the caps g bolted to the exten- I sions c any slack motionoccasioned by wear of the lips h, the upper faces of the extensions 6,or the bar f can be easily taken up by filing or planing the under faceof the caps or the upper face of the part of the extensions on which thesaid caps rest.

I am aware that an enforced tilting motion of the bridge of aprinting-press has been obtained by means of a guide-plate extendingdownward from the bridge, having therein a slot, onev part of which iscurved and the other and lower portion straight, and a stud whichprojects from the side of the table or frame.

plate traverses the stud, which insures a true rolling action of therockers. In this construction the curve of the slot must bear a As thebridge isthrown back, this certain relation to that of the rocker, andthe tilting of the bridge is necessarily gradual. \Vith my straightinclined faces the tilting 1s effected suddenly, and the platen issooner brought toan inclined position, so that the sheet to be printedmay be placed thereon.

I am further aware that it is not new in a printing-'pressto provide therocker with an ear having lugs adapted to be drawn over a portion of theframe, and thereby form a lock.

I claim as my invention 1. In a printing-press, the frame thereof havinglugs provided on their inner sides with grooves and inclined straightfaces leading therefrom, as shown, combined with the bridge havingrockers which rest on the said frame, and pins carrying rollers whichrest in the said lugs, and, as the bridge carrying the platen is drawntoward the bed of the press, follow the said inclined straight faces tothe said grooves, which they enter, and thereby bring the bridge andplaten into a vertical position and hold them in said position while theimpression is being made, substantially as and for the purposespecifled.

2. The bridge H, having the extensions 0, provided wit-h the removablecap-pieces 9, having the lips h, substantially as and for the purposespecified,

JOHN F. w] DORMAN.

